An integrated program of research is proposed to investigate, at varying stages of life-span development, the distribution of the human's attentional and processing resources in responding to visual and auditory inputs. Specifically, the research poses four questions. (1) How is the detectability of visual signals influenced by (a) the proportion of information specifying each stimulus and (b) the "size" of the cognitive unit presented? This question will be addressed with a detection task in which the proportion of information specifying a pictorial or verbal target item is varied and the cognitive content of the presented configuration is manipulated by contextual information. (2) How is the experienced duration of brief (less than 100 ms) visual stimuli influenced by amount of presented information? This question will be asked by requiring Ss to report which of two paired temporal intervals appears longer when the cognitive content of the presented stimuli is manipulated. (3) How is the integration of portions of a stimulus over time influenced by the cognitive content of the complete stimulus? To ask this question, Ss will be asked to judge the simultaneity or succession of sequenced, mutually exclusive, segments of a target whose cognitive content is varied. (4) How are attentional and processing resources distributed to simultaneous, and temporally patterned, visual and auditory events? This question will be indexed in the detection latency of detecting a target item in a temporally patterned visual input as the detection latency is influenced by a simultaneous auditory pattern whose organizational properties are varied. Experimental designs incorporate signal detection measures and analysis of variance for data evaluation.